Intravascular Ultrasound Evidence for Coarctation Causing Symptomatic Renal Artery Stenosis

Abstract

Background-A recent study of human cadaveric renal arteries revealed that renal artery narrowing could be due not only to atherosclerotic plaque compensated for by adaptive remodeling, but also to hitherto undescribed focal narrowing of an otherwise normal renal arterial wall (ie, coarctation). The present study investigated whether vessel coarctation could be identified in patients with symptomatic renal artery stenosis (RAS). Methods and Results-Consecutive symptomatic patients with angiographically proven atherosclerotic RAS who were referred for stent placement were studied by 30-MHz intravascular ultrasound before intervention (nϭ18) or after predilatation (nϭ18). Analysis included assessment of the media-bounded area and plaque area (PLA) at the most stenotic site and at a distal reference site (most distal cross-section in the main renal artery with normal appearance).Coarctation was considered present whenever the target/reference media-bounded area was Յ85%. Before intervention, coarctation was observed in 9 of 18 patients and adaptive remodeling in 9 of 18 patients. Coarctation lesions had a significantly smaller PLA than adaptive remodeled lesions (Pϭ0.001). Similarly, despite predilatation, coarctation was seen in 8 of 18 patients who had significantly smaller PLAs (Pϭ0.008) when compared with those patients who had adaptive remodeled lesions. No differences in severity of RAS or angiographic or clinical parameters were observed. Conclusions-Low-plaque coarctation may cause a considerable proportion of symptomatic RAS, which is angiographically and clinically indistinguishable from plaque-rich RAS. (Circulation. 1999;99:2976-2978.)

Association of Plaque Composition and Vessel Remodeling in Atherosclerotic Renal Artery Stenosis

“…The stenotic lesion including the slice with minimum lumen area was typically in the proximal part of the main renal artery near ostium of aorta in most cases. Therefore, in our study, the reference site was selected in the distal part of the main renal artery, and positive remodeling was defined as RI >1.05, as previous reports suggested (11,15,17,26). …”

“…Leertouwer et al (11) studied symptomatic RAS in vivo, and reported that coarctation of renal arteries, which was defined as RI <0.85, was prevalent in 50% of cases. Pasterkamp et al (26) reported that the prevalence of renal vascular enlargement was significantly higher compared with that of vascular shrinkage (8%) in mild or moderate atherosclerosis.…”

“…Such adaptive enlargement of vessels can compensate for the accumulation of atherosclerotic plaque in vivo to preserve the vessel lumen (8). The remodeling process has not been elucidated in atherosclerotic RAS, and intravascular ultrasound imaging (IVUS) may be feasible and useful for the assessment of atherosclerotic RAS (9–11). …”

Intravascular ultrasound-supported percutaneous angioplasty of post-kidney transplant renal artery bifurcation stenosis

“…Post-intervention IVUS helped us to achieve optimal results of all the intervened arterial segments, as reported by other authors, especially for native RAS. 15,16 There are only few published case reports about the use of IVUS in TRAS, [17][18][19] and none for the complex bifurcation lesion as was studied in the index case. Touma et al in a series of 17 patients with TRAS reported higher freedom from intervention and stenosis-free patency with stenting compared to balloon angioplasty (88.2% vs. 76.5%).…”

Predictors for Clinical Success at One Year following Renal Artery Stent Placement

“…Two atherosclerotic renal artery lesion types have been described based on IVUS criteria: one due to accumulation of atherosclerotic plaque with or without adaptive remodeling (adaptive remodeling lesion) and the other due to focal narrowing of the vessel wall without plaque accumulation (coarctation lesion). 12 Adaptive remodeling lesions have a larger vessel area at the target site than at the reference site (relative target-toreference vessel area of Ͼ85%), so lesions with a relative target-to-reference vessel area Յ85% were considered to be of the coarctation type.…”